Lanolin (refined and neutralized wool grease) has a unique combination of emulsifying ability, emolliency and ability to absorb water which makes it extremely useful in a variety of cosmetic and pharmaceutical formulations. Numerous products such as hand, face and body creams and lotions, lipsticks and lip glosses, shampoos, hair preparations, body and both oils, make-ups, facial masks and suntan preparations utilize lanolin to impart desirable characteristics to the formulation. Lanolin is also useful in the textile industry as a softening agent and finds some use in industrial lubricating applications because of the anti-corrosive and rust preventive properties of the compound.
Anhydrous lanolin U.S.P. is described as a yellow, tenacious unctuous mass having a slight characteristic odor. It is insoluble in water but mixes without separation with about twice its weight of water. The product has a slight acid value and melts at about 36-42.degree. C. Lanolin is a complex mixture of long-chain esters derived from higher alcohols, predominantly fused ring alcohols (sterols), and fatty acids and is one of the few natural fatty materials that contains a high percentage (.about.50%) of esterified hydroxy acids.
U.S.P. lanolin is not without some disadvantages in certain formulations. For example, a problem can arise due to incompatibility of the lanolin with hydrocarbon oils, the product may exhibit an undesirable amount of tackiness or emulsion stability may be unsatisfactory. For these reasons various derivatives of lanolin such as the ethoxylated and acylated derivatives have been developed. Lanolin can also be fractionated to obtain a more cosmetically elegant liquid form which has superior properties and improved compatibility with mineral oils. One such fractionation method utilizes a solvent crystallization process such as described in U.S. Pat. No. 2,758,125. Upon fractionation, in addition to obtaining the highly useful lanolin oil fraction, a solid fraction which is typically a hard waxy material melting at about 50.degree. C is obtained. The high melting lanolin wax fraction has found some limited use in the cosmetic industry but because of its undesirable physical form it is more generally used in such products as shoe polishes, floor and furniture polishes, printing inks and carbon paper inks.